Air conditioner

ABSTRACT

An air conditioner includes: an air passage  23  that is formed in a cabinet  20  so as to connect a suction port  21  and a blowoff port  22  to each other, which are open on a surface of the cabinet  20 ; a blower fan  25  that is disposed inside the air passage  23  so as to extend in one direction; a heat exchanger  27  that is disposed so as to be opposed to the suction port  21  and cools air flowing in through the suction port  21 ; a heater  28   a  that is disposed between the blower fan  25  and the heat exchanger  27  in order to heat air flowing in through the suction port  21  and is shorter in a longitudinal direction than the blower fan  25 ; a control element  52  that controls the heater  28   a  and is disposed outside the air passage  23  adjacently to the air passage  23 ; and a heat sink  70  that is in close contact with the control element  52  and is disposed between the blower fan  25  and the heat exchanger  27 , on an outside of the heater  28   a  in the longitudinal direction.

This application is based on Japanese Patent Application No. 2010-046934 filed on Mar. 3, 2010, the contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an air conditioner including a heater and a control element that controls the heater.

2. Description of Related Art

A conventional air conditioner is disclosed in JP-A-H8-152179. This air conditioner is configured as an integrated type in which an indoor section that is disposed indoors is installed at its front portion, and an outdoor section that is disposed outdoors is installed at its back portion. In the outdoor section, a compressor that operates a refrigeration cycle is disposed. At the rear surface of the outdoor section, an outdoor heat exchanger that is connected to the compressor is disposed, and an outdoor fan that cools the outdoor heat exchanger is provided so as to face the outdoor heat exchanger.

A suction port is open on the front surface of the indoor section, and a blowoff port is open at a position above the suction port. In the indoor section, an air passage is formed that is constituted by a blower duct connecting the suction port and the blowoff port to each other, and a blower fan is provided inside the air passage. Between the blower fan and the suction port, an indoor heat exchanger is disposed that is connected to the compressor via a refrigerant pipe. Between the blower fan and the indoor heat exchanger, a PTC (positive temperature coefficient) heater is disposed.

Upon the start of a cooling operation, the compressor is driven to operate the refrigeration cycle. In this operation, the indoor heat exchanger functions as an evaporator on a low temperature side of the refrigeration cycle, and the outdoor heat exchanger functions as a condenser on a high temperature side of the refrigeration cycle. The outdoor fan is driven to cause the outdoor heat exchanger to exchange heat with the outside air thereby to radiate heat. The blower fan is driven to cause air inside a room to flow into the air passage through the suction port and the air cooled by heat exchange with the indoor heat exchanger to be sent out into the room through the blowoff port. Thus, cooling of the room is performed.

Upon the start of a heating operation, the compressor is driven to operate the refrigeration cycle. In this operation, the indoor heat exchanger functions as the condenser on the high temperature side of the refrigeration cycle, and the outdoor heat exchanger functions as the evaporator on the low temperature side of the refrigeration cycle. The outdoor fan is driven to cause the outdoor heat exchanger to exchange heat with the outside air thereby to absorb heat. The blower fan is driven to cause air inside a room to flow into the air passage through the suction port, which is then heated by heat exchange with the indoor heat exchanger. Furthermore, by the driving of the PTC heater, the air inside the air passage is further heated. The air thus heated is sent out into the room through the blowoff port, and thus heating of the room is performed.

The PTC heater is made up of a heat generation element having PTC characteristics and electrodes sandwiching the heat generation element therebetween, and a voltage is applied between the electrodes to drive the PTC heater. When the heat generation element is heated to a temperature higher than its Curie point, the resistance value thereof increases rapidly, leading to a decrease in the current value and heat generation amount of the heat generation element. This stabilizes the heat generation amount of the PTC heater, so that hot air at a predetermined temperature can be easily generated, and the occurrence of overheating can be prevented.

In this case, however, at start-up, the PTC heater is at a low temperature and the heat generation element therefore has a low resistance value, so that an overcurrent might flow to exceed a tolerable current level based on a power supply capacitance. As a solution to this, JP-A-2003-59623 discloses a method of controlling the driving of a PTC heater, in which an electric current flowing through the PTC heater at start-up is monitored in order to prevent the electric current from exceeding a tolerable current level based on a power supply capacitance. That is, by a control circuit employing a triac element, duty control of the PTC heater is performed so that, at start-up, the PTC heater is driven with the duty ratio thereof increased gradually. This can prevent an overcurrent from occurring at the start-up of the PTC heater.

According to the above-described conventional air conditioner, however, due to a large heat generation amount of the triac element, electrical equipment provided in the air conditioner are heated. This impairs the safety of the air conditioner, which has been problematic. Furthermore, installing a fan for cooling the triac element increases the power consumption and cost of the air conditioner, which is also problematic.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an air conditioner that achieves a reduction in power consumption and cost and can improve safety.

In order to achieve the above-described object, the present invention includes: an air passage that is formed in a cabinet so as to connect a suction port and a blowoff port to each other, which are open on a surface of the cabinet; a blower fan that is disposed inside the air passage so as to extend in a longitudinal direction; a heat exchanger that is disposed so as to be opposed to the suction port and exchanges heat with air flowing in through the suction port; a heater that is disposed between the blower fan and the heat exchanger in order to heat air flowing in through the suction port and is shorter in a longitudinal direction than the blower fan; a control element that controls the heater and is disposed outside the air passage adjacently to the air passage; and a heat sink that is in close contact with the control element and is disposed between the blower fan and the heat exchanger, on an outside of the heater in the longitudinal direction.

According to this configuration, when a cooling operation is performed, air taken from a room into the air passage through the suction port by the driving of the blower fan exchanges heat with the heat exchanger and thus is cooled, and the air is then sent out into the room through the blowoff port. When a heating operation is performed, air taken from the room into the air passage through the suction port by the driving of the blower fan is heated by the heater that is controlled by the control element. During the heating operation, the air flowing through the air passage may be further heated by the heat exchanger. The control element is disposed outside the air passage adjacently to the air passage, and in order to avoid heat radiation of the heater, the heat sink in close contact with the control element is disposed between the blower fan and the heat exchanger, on the outside of the heater in the longitudinal direction. The control element is cooled by an airflow flowing through the air passage via the heat sink.

The control element that controls the heater is disposed adjacently to the air passage and the heat sink is disposed inside the air passage, and thus the control element can be cooled by an airflow flowing through the air passage via the heat sink. This eliminates the need to install a fan for cooling the control element, and thus power consumption and cost can be reduced and the safety of the air conditioner can be improved.

Furthermore, in the longitudinal direction, the heat sink is disposed on the outside of the heater that is shorter than the blower fan, and thus the temperature rise of the control element due to heat radiation of the heater can be suppressed. Moreover, air heated by heat exchange with the heat sink is sent out from an end portion of the air passage, and thus the efficiency of a heating operation can be improved. In addition, the heat sink is disposed in a dead space between the blower fan and the heat exchanger, on the outside of the heater in the longitudinal direction, and thus the air conditioner can be prevented from increasing in size due to the installation of the heat sink.

Furthermore, in the present invention, preferably, in the air conditioner configured as above, the heater is formed by a PTC heater, and the control element is formed by a triac element. According to this configuration, duty control of the PTC heater is performed by the triac element, and thus the occurrence of an overcurrent at the start-up of the PTC heater is prevented.

Furthermore, in the present invention, more preferably, the air conditioner configured as above further includes: a circuit substrate on which the control element is mounted; a cup-shaped substrate holder that has a window portion for inserting the control element thereinto, open on an opposed surface of the substrate holder, which is opposed to the heat sink, and holds the circuit substrate; and a molding material that is filled in the substrate holder so as to mold the circuit substrate and the control element.

According to this configuration, the circuit substrate is disposed in the cup-shaped substrate holder, and the control element mounted on the circuit substrate is brought into close contact with the heat sink via the window portion. The molding material is filled in the substrate holder, so that the circuit substrate is molded and the control element disposed at the window portion is also molded. In a case where, during a cooling operation, low temperature air comes in contact with the heat sink and thus dew condensation occurs in the substrate holder, since the molding material is filled, it is possible to prevent dew condensation water from being deposited on the circuit substrate and the control element.

Furthermore, in the present invention, the air conditioner configured as above may have the following configuration. That is, the heat sink has a guide groove that is recessed therein so as to extend in one direction, and the substrate holder has a fitting portion to be fitted into the guide groove. Further, the width between both side walls of the guide groove is set to be greater at least part of a region between the side walls than at an open surface of the guide groove, and through fitting between the guide groove and the fitting portion, the substrate holder is guided to be slid in the one direction. According to this configuration, the fitting portion of the substrate holder is inserted in a sliding manner from one direction into the guide groove of the heat sink, after which the circuit substrate is disposed in the substrate holder, and the control element is mounted to the heat sink.

Furthermore, in the present invention, the air conditioner configured as above may have the following configuration. That is, an engaging protrusion is provided on the opposed surface of the substrate holder, and an engaging hole is provided in the heat sink, which is engaged with the engaging protrusion so that positioning of the heat sink and the substrate holder relative to each other is performed. According to this configuration, the fitting portion of the substrate holder is slid from one direction into the guide groove of the heat sink, and the engaging protrusion is engaged with the engaging hole, by which positioning of the substrate holder is performed.

Furthermore, in the present invention, more preferably, in the air conditioner configured as above, the control element is fastened to the heat sink with a screw, and a groove portion into which the control element is fitted is recessed in the heat sink. According to this configuration, the control element is installed by being fitted into the groove portion of the heat sink and then is fastened thereto with a screw. At this time, the groove portion prevents the control element from being rotated due to the screw being firmly screwed down.

Furthermore, in the present invention, more preferably, in the air conditioner configured as above, an opening portion is formed on one of wall surfaces of the air passage in the longitudinal direction, and a heat sink holder is provided that has an arm portion made of an elastic body and used to sandwich two circumferential surfaces of the heat sink, which are opposed to each other, and is mounted to the one of wall surfaces of the air passage by being fitted into the opening portion. According to this configuration, while holding the two surfaces of the heat sink between the arm portions that are deformed elastically, the heat sink holder is fitted into the opening portion and mounted to the wall surface of the air passage by, for example, being fastened thereto with a screw.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an air conditioner according to an embodiment of the present invention.

FIG. 2 is a cross-sectional side view showing the air conditioner according to the embodiment of the present invention.

FIG. 3 is a front view showing the air conditioner according to the embodiment of the present invention.

FIG. 4 is a perspective view showing an intermediate wall of the air conditioner according to the embodiment of the present invention.

FIG. 5 is a perspective view showing a control circuit unit of the air conditioner according to the embodiment of the present invention.

FIG. 6 is an exploded perspective view showing the control circuit unit of the air conditioner according to the embodiment of the present invention.

FIG. 7 is a cross-sectional side view showing a heat sink and a substrate holder of the control circuit unit of the air conditioner according to the embodiment of the present invention, in a state where they are fitted to each other.

FIG. 8 is a front view showing the heat sink and the substrate holder of the control circuit unit of the air conditioner according to the embodiment of the present invention, in the state where they are fitted to each other.

FIG. 9 is a cross-sectional top view showing the heat sink and the substrate holder of the control circuit unit of the air conditioner according to the embodiment of the present invention, in the state where they are fitted to each other.

FIG. 10 is a perspective view showing a wiring state of the control circuit unit of the air conditioner according to the embodiment of the present invention.

FIG. 11 is a front view showing the heat sink and a heat sink holder of the control circuit unit of the air conditioner according to the embodiment of the present invention, in a state before they are fitted to each other.

FIG. 12 is a front view showing the heat sink and the heat sink holder of the control circuit unit of the air conditioner according to the embodiment of the present invention, in a state where they are fitted to each other.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The following describes an embodiment of the present invention with reference to the appended drawings. FIGS. 1, 2, and 3 are a perspective view, a cross-sectional side view, and a front view showing an air conditioner according to one embodiment, respectively. FIGS. 1 and 3 show a state without an exterior cover 30 (see FIG. 2). An air conditioner 1 is configured as an integrated type including an indoor section 2 that is disposed indoors and an outdoor section 4 that is disposed outdoors adjacently to the indoor section 2.

A suction port 21 is provided in a front portion of the indoor section 2, and an outdoor heat exchanger 42 is provided in a front portion of the outdoor section 4. In the following description, a front side refers to a suction port 21 side, and a back side (rear side) refers to an outdoor heat exchanger 42 side. Furthermore, a right side and a left side of the air conditioner 1 refer to the right side and the left side thereof in a view facing the suction port 21 from the front, respectively.

The indoor section 2 and the outdoor section 4 are installed on a bottom plate 3, and a partition wall 5 is provided so that the indoor section 2 on the front side and the outdoor section 4 on the back side are separated from each other. The indoor section 2 constitutes a cabinet 20 surrounded on its outer side by the bottom plate 3, the partition wall 5, and the exterior cover 30. At a right end portion in the cabinet 20, an electrical equipment box 31 containing electrical equipment is provided. Similarly to the indoor section 2, the outdoor section 4 constitutes a cabinet 40 surrounded on its outer side by the bottom plate 3, the partition wall 5, and an exterior cover (not shown).

In the outdoor section 4, a compressor 41 that operates a refrigeration cycle is disposed at an end portion on the right side. At the rear surface of the outdoor section 4, the outdoor heat exchanger 42 that is connected to the compressor 41 via a refrigerant pipe 47 is disposed. An outdoor fan 43 formed by a propeller fan is disposed at a center portion in the lateral direction in a view facing the outdoor heat exchanger 42 and cools the outdoor heat exchanger 42. The outdoor fan 43 and the outdoor heat exchanger 42 are disposed in a housing 44 that is supported by the partition wall 5 via a bracket 45. The housing 44 constitutes a duct that guides an airflow from the outdoor fan 43 to the outdoor heat exchanger 42.

The suction port 21 is open on the front surface of the exterior cover 30 covering the indoor section 2, and a blowoff port 22 is open at a position above the suction port 21. In the indoor section 2, an air passage 23 is provided that connects the suction port 21 and the blowoff port 22 to each other. The rear surface and side surfaces of the air passage 23 are constituted by an intermediate wall 24 mounted on the bottom plate 3. A wall of the air passage 23 below and in the vicinity of the blowoff port 22 is constituted by a duct member 29 that can be mounted and demounted when the exterior cover 30 is removed. A louver 26 that can change a direction in which air is blown out through the blowoff port 22 is mounted to the duct member 29.

Inside the air passage 23, a blower fan 25 formed by a cross-flow fan is provided so as to extend in the lateral direction. Between the blower fan 25 and the suction port 21, an indoor heat exchanger 27 that is connected to the compressor 41 via the refrigerant pipe 47 is disposed so as to be opposed to the suction port 21. The indoor heat exchanger 27 is provided in the longitudinal direction of the blower fan 25 so as to have substantially the same width as that of the blower fan 25. Below the indoor heat exchanger 27, a drain pan 32 is disposed that collects dew condensation water from the indoor heat exchanger 27 and drains it to the outside. The drain pan 32 extends to below a control circuit unit 50, which is described later, and collects dew condensation water produced from the control circuit unit 50.

A heater unit 28 is disposed between the blower fan 25 and the indoor heat exchanger 27. As described later, the heater unit 28 is held by an angle 80 fastened with a screw to a side surface portion 24 a (see FIG. 4) of the intermediate wall 24. The indoor heat exchanger 27 and the heater unit 28 are covered above by the duct member 29. When the screw used for mounting the angle 80 is unscrewed and the duct member 29 is removed, the heater unit 28 can be mounted and demounted from above.

The heater unit 28 is formed by lamination of a PTC heater 28 a made up of a semiconductor element and electrodes sandwiching the semiconductor element therebetween and a fin 28 b of a honeycomb structure. The PTC heater 28 a is shorter in the longitudinal direction than the blower fan 25, and inside the air passage 23, a space portion 33 is formed on the right side of the PTC heater 28 a. In the space portion 33, a terminal portion 28 c of the heater unit 28 is disposed.

The control circuit unit 50 including a triac element 52 that controls the PTC heater 28 a is disposed behind the terminal portion 28 c. By the triac element 52, duty control of the PTC heater 28 a is performed so that, at start-up, the PTC heater 28 a is driven with the duty ratio thereof increased gradually. This can prevent an overcurrent from occurring at the start-up of the PTC heater 28 a.

FIG. 4 shows a perspective view of the intermediate wall 24. The intermediate wall 24 has the side surface portion 24 a constituting each of side walls of the air passage 23, and an opening portion 24 b is provided on a right-side one of the side surface portions 24 a. The control circuit unit 50 is mounted to the opening portion 24 b astride the inside and outside of the air passage 23. At this time, a heat sink 70 (see FIG. 5) is disposed inside the air passage 23, and a substrate holder 60 (see FIG. 5) is disposed on the outside of the air passage 23.

FIGS. 5 and 6 show a perspective view and an exploded perspective view of the control circuit unit 50, respectively. The control circuit unit 50 includes a circuit substrate 51, a substrate holder 60, a lid portion 68, the heat sink 70, and a heat sink holder 78. The triac element 52 is mounted on the circuit substrate 51 and disposed in the cup-shaped substrate holder 60 made of a resinous molded article. As described later in detail, the substrate holder 60 is fitted to the heat sink 70, and an opening surface of the substrate holder 60 is closed with the lid portion 68 made of a resinous molded article.

FIGS. 7, 8, and 9 are a cross-sectional side view, a front view, and a cross-sectional top view showing a state where the substrate holder 60 and the heat sink 70 are fitted to each other, respectively. The heat sink 70 is formed by extrusion molding of aluminum, and a plurality of the fins 71 are provided in a protruding manner on one surface of the heat sink 70.

On a reference surface 70 a of the heat sink 70 on the side opposite to the surface on which the fins 71 are formed, a guide groove 73 is provided so as to extend in the vertical direction. The guide groove 73 is formed by a croze whose both side walls are inclined and that thus is trapezoidal in cross section, and the width between the side walls of the guide groove 73 is set to be greater at part of a region between the side walls than at an open surface of the guide groove 73. Part of the side walls of the guide groove 73 may be formed in a squared U-shape in cross section so that the width between the side walls is made greater at part of the region between the side walls than at the open surface. On the bottom surface of the guide groove 73, a groove portion 72 squared U-shaped in cross section is recessed so as to extend in the vertical direction. At an upper portion of the bottom surface of the groove portion 72, a screw hole 74 is provided, and at a lower portion thereof, an engaging hole 75 is recessed.

In the substrate holder 60, a window portion 64 is open at an upper portion of an opposed surface 60 a thereof, which is opposed to the heat sink 70. On both sides of the window portion 64 on the opposed surface 60 a, a fitting portion 61 to be fitted into the guide groove 73 is provided in a protruding manner at a plurality of positions. At a lower portion of the opposed surface 60 a, an engaging protrusion 63 is provided in a protruding manner. Furthermore, a plurality of L-shaped ribs 62 are provided on the inner circumferential surface of the substrate holder 60.

In assembling the control circuit unit 50, first, as shown by an arrow A1 (see FIG. 6), the fitting portions 61 of the substrate holder 60 are inserted from below into the guide groove 73 of the heat sink 70. The substrate holder 60 thus is guided by the guide groove 73 to be slid upward, and at a time when the engaging protrusion 63 is engaged with the engaging hole 75, positioning of the heat sink 70 and the substrate holder 60 relative to each other is achieved. This eliminates the need to fasten the substrate holder 60 to the heat sink 70 with a screw, and thus the substrate holder 60 can be easily fixed.

Next, the circuit substrate 51 is mounted on the ribs 62 in the substrate holder 60. A terminal 52 b of the triac element 52 is bent, and the triac element 52 is disposed parallel to the circuit substrate 51. The triac element 52 is fitted into the groove portion 72 of the heat sink 70 via the window portion 64. Then, as shown by an arrow A2 (see FIG. 6), a screw 57 (see FIG. 6) is inserted into a through hole 52 a provided at an upper portion of the triac element 52 and screwed into the screw hole 74. Thus, the triac element 52 is fixed to the heat sink 70 so as to be in close contact therewith.

At this time, since the triac element 52 is fitted into the groove portion 72 of the heat sink 70, the triac element 52 is prevented from being rotated due to the screw 57 being firmly screwed down. This can prevent the terminal 52 b of the triac element 52 from being warped to be broken. Furthermore, at the time of firmly screwing down the screw 57, the circuit substrate 51 is not fixed to the substrate holder 60, which can more reliably prevent the terminal 52 b of the triac element 52 from being warped to be damaged.

Furthermore, at an upper end of the circuit substrate 51, a concave portion 51 a from which the through hole 52 a is exposed is formed by cutting out a portion of the circuit substrate 51, which is opposed to the through hole 52 a. The triac element 52 is fixed with the screw 57 via the concave portion 51 a. This can reduce the amount of two-dimensional protrusion of the triac element 52 from the circuit substrate 51. Thus, the substrate holder 60 can be reduced in size and thereby allows the control circuit unit 50 to be reduced in size, and the amount of a molding material 58 used, which is described later, can be reduced.

After the triac element 52 is mounted to the heat sink 70, the molding material 58 made of a resin such as urethane is filled in the substrate holder 60. Through hardening of the molding material 58, the circuit substrate 51 and the triac element 52 are molded, and thus the circuit substrate 51 is fixed. In this case, prior to the hardening, part of the molding material 58, which flows along a gap between the periphery of the window portion 64 and the heat sink 70, is prevented by surface tension from flowing out to the periphery of the substrate holder 60. A shielding material that prevents the molding material 58 from flowing out may be provided at the periphery of the substrate holder 60.

If, during a cooling operation, low temperature air flowing through the air passage 23 comes in contact with the heat sink 70, dew condensation may occur in the substrate holder 60. In such a case, since the molding material 58 is filled, it is possible to prevent dew condensation water from being deposited on the circuit substrate 51 and the triac element 52.

Furthermore, the triac element 52 is disposed at an upper portion in the substrate holder 60. If voids are formed in the molding material 58, dew condensation water on the surface of the molding material 58 may reach the triac element 52. In such a case, since the triac element 52 is disposed at the upper portion in the substrate holder 60, the possibility that dew condensation water reaches the triac element 52 can be reduced to a greater degree than in the case where the triac element 52 is disposed at a lower portion in the substrate holder 60.

FIG. 10 is a perspective view showing a state where the circuit substrate 51 is fixed by filling the molding material 58. A lead 59 extending from the circuit substrate 51 is taken out through an opening portion 65 that is open on the lower surface of the substrate holder 60. The lead 59 is bent into a U-shape below the substrate holder 60 and is guided upward by a holding portion 66 that is provided on a side surface of the substrate holder 60.

The lead 59 is connected to the inside of the electrical equipment box 31 (see FIG. 3) via an opening portion (not shown) provided at an upper portion of the electrical equipment box 31. Thus, dew condensation water produced in the substrate holder 60 and allowed to slip along the lead 59 drips from a lower end of the lead 59 onto the drain pan 32 (see FIG. 3) and thus is collected. This can prevent the entry of dew condensation water into the electrical equipment box 31.

Next, as shown by an arrow A3 (see FIG. 6), the opening surface of the substrate holder 60 is closed with the lid portion 68. On the inner surface of the lid portion 68, a housing portion 68 a is recessed so as to be opposed to the opening portion 65 of the substrate holder 60 and to extend in the vertical direction. The lead 59 is disposed in the housing portion 68 a, which allows the lead 59 to be bent at an increased radius of curvature. This can prevent breakage of the lead 59. Furthermore, this can also prevent the lead 59 from being displaced in the lateral direction.

Next, using the heat sink holder 78, holding of the heat sink 70 is performed. FIGS. 11 and 12 are front views showing a state before the heat sink 70 and the heat sink holder 78 are fitted to each other and a state where they have been fitted to each other, respectively. The heat sink holder 78 is made of a resinous molded article, and at each of two portions thereof, which are upper and lower portions of the heat sink holder 78, an arm portion 78 a that constitutes an elastic body is provided in a protruding manner so as to extend in one direction. The arm portion 78 a is formed in an L-shape in cross section and has a standing portion 78 c that is to lie along the reference surface 70 a of the heat sink 70. At a tip end of the arm portion 78 a, a nail portion 78 b is formed so as to be opposed to the standing portion 78 c.

As shown by an arrow A4, the heat sink 70 is inserted between both the arm portions 78 a while causing the arm portions 78 a to be bent elastically during the insertion. At this time, the standing portion 78 c comes to lie along the reference surface 70 a of the heat sink 70, and the nail portion 78 b provided at the tip end of the arm portion 78 a is engaged with the fins 71. The arm portions 78 a thus sandwich therebetween two surfaces of the heat sink 70, which are opposed to each other in the vertical direction, and thereby holds the heat sink 70.

The heat sink holder 78 is fitted into the opening portion 24 b (see FIG. 4) of the intermediate wall 24. Then, a screw is inserted into a through hole 78 d provided at each of upper and lower ends of the heat sink holder 78 and into a through hole (not shown) provided on the periphery of the opening portion 24 b and screwed to be secured to a screw portion 80 a (see FIG. 3) of the angle 80. Thus, the control circuit unit 50 is mounted to the intermediate wall 24.

At this time, the substrate holder 60 containing the triac element 52 is disposed outside the air passage 23 adjacently to the air passage 23. The heat sink 70 in close contact with the triac element 52 protrudes into the air passage 23 and is disposed between the blower fan 25 and the indoor heat exchanger 27, on the outside of the PTC heater 28 a in the longitudinal direction.

A common screw is used for mounting the angle 80 and the control circuit unit 50 to the intermediate wall 24, and thus the number of components used can be reduced. Furthermore, the use of the arm portions 78 a allows the heat sink 70 to be easily held and thus eliminates the need for a screw for fitting the heat sink 70 and the heat sink holder 78 to each other, so that the number of components used can be reduced. In addition, the arm portions 78 a are fitted onto the inner circumferential surface of the opening portion 24 b while covering the upper and lower surfaces of the guide groove 73, and thus it is possible to prevent air from leaking from the air passage 23 via the guide groove 73.

In the air conditioner 1 configured as above, upon the start of a cooling operation, the compressor 41 is driven to operate the refrigeration cycle. In this operation, the indoor heat exchanger 27 functions as an evaporator on a low temperature side of the refrigeration cycle, and the outdoor heat exchanger 42 functions as a condenser on a high temperature side of the refrigeration cycle. The outdoor fan 43 is driven to cause the outdoor heat exchanger 42 to exchange heat with the outside air thereby to radiate heat. The blower fan 25 is driven to cause air inside a room to flow into the air passage 23 through the suction port 21 and the air cooled by heat exchange with the indoor heat exchanger 27 to be sent out into the room through the blowoff port 22. Thus, cooling of the room is performed.

Upon the start of a heating operation, the compressor 41 is driven to operate the refrigeration cycle. In this operation, the indoor heat exchanger 27 functions as the condenser on the high temperature side of the refrigeration cycle, and the outdoor heat exchanger 42 functions as the evaporator on the low temperature side of the refrigeration cycle. The outdoor fan 43 is driven to cause the outdoor heat exchanger 42 to exchange heat with the outside air thereby to absorb heat. The blower fan 25 is driven to cause air inside a room to flow into the air passage 23 through the suction port 21, which is then heated by heat exchange with the indoor heat exchanger 27.

Furthermore, by the driving of the PTC heater 28 a, the air flowing through the air passage 23 is further heated. In this regard, the blower fan 25 and the indoor heat exchanger 27 are formed so as to extend further to the lateral sides than the PTC heater 28 a. This can increase a heat exchange area of the indoor heat exchanger 27. Furthermore, air flowing through the space portion 33 on the lateral side of the PTC heater 28 a cools the triac element 52 via the heat sink 70. At this time, the air flowing through the space portion 33 exchanges heat with the heat sink 70 and thus is heated.

The air heated by the indoor heat exchanger 27 and the PTC heater 28 a is sent out into the room through the blowoff port 22, and thus heating of the room is performed.

During a heating operation, the compressor 41 may be deactivated so that air is heated by the PTC heater 28 a alone. Furthermore, an integrated air conditioner capable only of cooling based on the operation of a refrigeration cycle may be modified so that a heating operation by the PTC heater 28 a is enabled.

According to this embodiment, the triac element 52 that controls the PTC heater 28 a is disposed adjacently to the air passage 23 and the heat sink 70 is disposed inside the air passage 23, and thus the triac element 52 can be cooled by an airflow flowing through the air passage 23 via the heat sink 70. This eliminates the need to install a fan for cooling the triac element 52, and thus power consumption and cost can be reduced and the safety of the air conditioner 1 can be improved.

Furthermore, in the longitudinal direction, the heat sink 70 is disposed on the outside of the PTC heater 28 a that is shorter than the blower fan 25, and thus the temperature rise of the triac element 52 due to heat radiation of the PTC heater 28 a can be suppressed. Moreover, air heated by heat exchange with the heat sink 70 is sent out from an end portion of the air passage 23, and thus the efficiency of a heating operation can be improved. In addition, the heat sink 70 is disposed in a dead space between the blower fan 25 and the indoor heat exchanger 27, on the outside of the PTC heater 28 a in the longitudinal direction, and thus the air conditioner 1 can be prevented from increasing in size due to the installation of the heat sink 70.

Furthermore, the substrate holder 60 is formed in a cup shape and has the window portion 64 open therein for inserting the triac element 52 thereinto, and by the molding material 58 filled in the substrate holder 60, the circuit substrate 51 and the triac element 52 are molded. Thus, in a case where, during a cooling operation, low temperature air comes in contact with the heat sink 70 and thus dew condensation occurs in the substrate holder 60, since the molding material 58 is filled, it is possible to prevent dew condensation water from being deposited on the circuit substrate 51 and the triac element 52.

Furthermore, in the heat sink 70, the guide groove 73 is so formed that the width between both the side walls thereof is greater at least part of the region between the side walls than at the open surface of the guide groove 73, and the substrate holder 60 has the fitting portion 61 to be fitted into the guide groove 73, so that the substrate holder 60 can be easily fitted to the heat sink 70. Furthermore, since there is no need for a screw for fitting the substrate holder 60 to the heat sink 70, it is possible to reduce a phenomenon in which, during a cooling operation, dew condensation occurs in the substrate holder 60 due to heat conduction via the screw.

Furthermore, the engaging protrusion 63 is provided in the substrate holder 60, and the engaging hole 75 is provided in the heat sink 70, so that through engagement between the engaging protrusion 63 and the engaging hole 75, positioning of the heat sink 70 and the substrate holder 60 relative to each other can be easily performed, and thus assembling workability can be improved.

Furthermore, the triac element 52 is fitted into the groove portion 72 recessed in the heat sink 70 and is fastened in that state with the screw 57, and thus the triac element 52 is prevented from being rotated due to the screw 57 being firmly screwed down. This can prevent the terminal 52 b of the triac element 52 from being warped to be broken.

Furthermore, the heat sink holder 78 has the arm portion 78 a that is made of an elastic body and used to sandwich the two circumferential surfaces of the heat sink 70, which are opposed to each other, and is mounted by being fitted into the opening portion 24 b on a wall surface of the air passage 23, so that the heat sink 70 can be easily held by the heat sink holder 78.

In this embodiment, air flowing through the air passage 23 is heated by the PTC heater 28 a that is controlled by the triac element 52 in close contact with the heat sink 70. There is, however, no limitation thereto. Heating may be performed using a heater that is controlled by a control element of another type provided in close contact with the heat sink 70.

The present invention can be applied to air conditioners each including a heater and a control element that controls the heater.

LIST OF REFERENCE NUMERALS

-   -   1 Air conditioner     -   2 Indoor section     -   3 Bottom plate     -   4 Outdoor section     -   5 Partition wall     -   20, 40 Cabinet     -   21 Suction port     -   22 Blowoff port     -   23 Air passage     -   24 Intermediate wall     -   24 b Opening portion     -   25 Blower fan     -   26 Louver     -   27 Indoor heat exchanger     -   28 Heater unit     -   28 a PTC heater     -   29 Duct member     -   30 Exterior cover     -   31 Electrical equipment box     -   41 Compressor     -   42 Outdoor heat exchanger     -   43 Outdoor fan     -   47 Refrigerant pipe     -   50 Control circuit unit     -   51 Circuit substrate     -   52 Triac element     -   58 Molding material     -   59 Lead     -   60 Substrate holder     -   61 Fitting portion     -   63 Engaging protrusion     -   64 Window portion     -   70 Heat sink     -   71 Fin     -   72 Groove portion     -   73 Guide groove     -   75 Engaging hole     -   78 Heat sink holder     -   78 a Arm portion 

1. An air conditioner, comprising: an air passage that is formed in a cabinet so as to connect a suction port and a blowoff port to each other, which are open on a surface of the cabinet; a blower fan that is disposed inside the air passage so as to extend in a longitudinal direction; a heat exchanger that is disposed so as to be opposed to the suction port and exchanges heat with air flowing in through the suction port; a heater that is disposed between the blower fan and the heat exchanger in order to heat air flowing in through the suction port and is shorter in a longitudinal direction than the blower fan; a control element that controls the heater and is disposed outside the air passage adjacently to the air passage; and a heat sink that is in close contact with the control element and is disposed between the blower fan and the heat exchanger, on an outside of the heater in the longitudinal direction.
 2. The air conditioner according to claim 1, wherein the heater is formed by a PTC heater, and the control element is formed by a triac element.
 3. The air conditioner according to claim 1 or 2, further comprising: a circuit substrate on which the control element is mounted; a cup-shaped substrate holder that has a window portion for inserting the control element thereinto, open on an opposed surface of the substrate holder, which is opposed to the heat sink, and holds the circuit substrate; and a molding material that is filled in the substrate holder so as to mold the circuit substrate and the control element.
 4. The air conditioner according to claim 3, wherein the heat sink has a guide groove that is recessed therein so as to extend in one direction, and the substrate holder has a fitting portion to be fitted into the guide groove, a width between both side walls of the guide groove is set to be greater at least part of a region between the side walls than at an open surface of the guide groove, and through fitting between the guide groove and the fitting portion, the substrate holder is guided to be slid in the one direction.
 5. The air conditioner according to claim 4, wherein an engaging protrusion is provided on the opposed surface of the substrate holder, and an engaging hole is provided in the heat sink, which is engaged with the engaging protrusion so that positioning of the heat sink and the substrate holder relative to each other is performed.
 6. The air conditioner according to claim 3, wherein the control element is fastened to the heat sink with a screw, and a groove portion into which the control element is fitted is recessed in the heat sink.
 7. The air conditioner according to claim 1 or 2, wherein an opening portion is formed on one of wall surfaces of the air passage in the longitudinal direction, and a heat sink holder is provided that has an arm portion made of an elastic body and used to sandwich two circumferential surfaces of the heat sink, which are opposed to each other, and is mounted to the one of wall surfaces of the air passage by being fitted into the opening portion. 